print debug msgs to stderr

2 files changed, 29 insertions, 7 deletions

diff --git a/src/lib/libsw602_utils.cpp b/src/lib/libsw602_utils.cpp
index 78f264c..1ae5dbf 100644
--- a/src/lib/libsw602_utils.cpp
+++ b/src/lib/libsw602_utils.cpp
@@ -7,10 +7,13 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
-#include <cstdio>
-
 #include "libsw602_utils.h"
 
+#include <cstdarg>
+#ifdef DEBUG
+#include <cstdio>
+#endif
+
 namespace libsw602
 {
 
@@ -125,6 +128,16 @@ void skip(librevenge::RVNGInputStream &input, unsigned long numBytes)
   }
 }
 
+#ifdef DEBUG
+void debugPrint(const char *const format, ...)
+{
+  va_list args;
+  va_start(args, format);
+  std::vfprintf(stderr, format, args);
+  va_end(args);
+}
+#endif
+
 }
 
 /* vim:set shiftwidth=2 softtabstop=2 expandtab: */
diff --git a/src/lib/libsw602_utils.h b/src/lib/libsw602_utils.h
index d8cbda2..e49c4c6 100644
--- a/src/lib/libsw602_utils.h
+++ b/src/lib/libsw602_utils.h
@@ -10,18 +10,23 @@
 #ifndef INCLUDED_LIBSW602_UTILS_H
 #define INCLUDED_LIBSW602_UTILS_H
 
-#ifdef DEBUG
-#include <cstdio>
-#endif
-
 #include <boost/cstdint.hpp>
 
 #include <librevenge-stream/librevenge-stream.h>
 #include <librevenge/librevenge.h>
 
+namespace libsw602
+{
+}
+
 // do nothing with debug messages in a release compile
 #ifdef DEBUG
-#define SW602_DEBUG_MSG(M) std::printf M
+#if defined(__clang__) || defined(__GNUC__)
+#  define SW602_ATTRIBUTE_PRINTF(fmt, arg) __attribute__((__format__(__printf__, fmt, arg)))
+#else
+#  define SW602_ATTRIBUTE_PRINTF(fmt, arg)
+#endif
+#define SW602_DEBUG_MSG(M) libsw602::debugPrint M
 #define SW602_DEBUG(M) M
 #else
 #define SW602_DEBUG_MSG(M)
@@ -58,6 +63,10 @@ const unsigned char *readNBytes(librevenge::RVNGInputStream &input, unsigned lon
 
 void skip(librevenge::RVNGInputStream &input, unsigned long numBytes);
 
+#ifdef DEBUG
+void debugPrint(const char *format, ...) SW602_ATTRIBUTE_PRINTF(1, 2);
+#endif
+
 class EndOfStreamException
 {
 };